Containers sealed by membranes find wide-commercial use. The enclosed contents, which include such varied materials as medicine, foodstuffs, cleaning products, or other household or automotive, may be liquids or solids. The latter may be in the form of powders, granules, or tablets. Depending on the application, the containers may vary widely in size and shape, from narrow-necked bottles to wide-mouthed jars, and may be formed from various materials such as plastic or glass.
A simple and convenient way of removing the membrane seal from a container to gain access to its contents is very desirable. It may also be important to prevent the cut membrane from falling into the container. Several approaches to opening a membrane-sealed container are described in the prior art.
U.S. Pat. No. 4,340,147 discloses a dual function cap for a necked container sealed with a membrane in which the piercing element is centered in a cup-like cap with tapered sidewalls.
U.S. Pat. No. 4,634,013 discloses a device for closing and opening a membrane-sealed bottle provided with means for cutting the membrane without pushing the membrane downward while cutting and means for allowing rotation of the cap less than 360 degrees so that the cut membrane is not completely detached from the bottle.
U.S. Pat. No. 4,709,822 discloses a child resistant upright bottle neck and cap combination that includes a cutter in a compartment on top of the cap. The compartment containing the cutter is placed over the neck containing a seal, which is cut by rotating the inverted cap.
U.S. Pat. No. 5,090,582 discloses a threaded bottle cap that includes a seal puncturing means which produces a C-shaped opening in the seal when the cap is rotated.
A cap used to enclose membrane-sealed containers may vary widely in its structure and mode of function. Typically molded from plastic, it may include a thread for securing it to a container with a threaded opening. Alternatively, the cap may be of a press-on design, whereby the container is closed by application of pressure on the cap against the opening and conversely is opened by lifting the cap away from the opening. The cap may also incorporate lock lugs for securing it to the container, opening being accomplished by aligning the lugs with channels in the neck of the container prior to separating it from the cap.
The membranes used to seal the contents of the container may serve purposes of safety and security, i.e., prevent contamination or tampering, or it may serve to insure freshness of contents such as foodstuffs. These membranes, which may be formed from a variety of materials such as plastic films, metal foils, paper, or composites of the same, exhibit differences in properties such as flexibility and toughness. The closure device of the present invention provides for the easy, convenient penetration of such membranes, even those of large cross-section on wide-mouthed containers, simply by pressing the cutters of the device against them.